The transcription factor BpERF1A enhances drought tolerance in Betula platyphylla by activating dehydrin and ROS scavenging through interaction with BpRAV1.

Abstract

Although ERF transcription factors (TFs) play critical roles in abiotic stress tolerance, the molecular mechanisms underlying this role remain incompletely understood. This study identified BpERF1A in birch (Betula platyphylla) as a drought-responsive TF through co-expression regulatory network analysis. Expression of BpERF1A was stalwartly induced by drought stress, and drought treatment markedly boosted its promoter activity. Functional analyses demonstrated that overexpression of BpERF1A markedly improved drought tolerance compared with wild-type (WT) birch, whereas its repression increased drought sensitivity. Overexpression lines also exhibited higher antioxidant enzyme activities and proline content relative to WT. Chromatin immunoprecipitation-polymerase chain reaction, yeast one-hybrid and dual-luciferase (dual-LUC) assays confirmed that BpERF1A directly binds to G-box elements in the promoters of BpDHN (dehydrin) and BpAOS (allene oxide synthase), activating their transcription. Furthermore, overexpression of BpDHN/BpAOS enhanced drought tolerance and promoted reactive oxygen species (ROS) scavenging in transgenic plants. Protein-protein interaction analysis using bimolecular fluorescence complementation revealed that BpERF1A interacts with BpRAV1 to form a heterodimer, which further enhances BpERF1A binding to the BpDHN promoter and its transcriptional activation. Collectively, these findings establish a central role for the BpERF1A regulatory module in drought acclimation and highlight its synergistic interaction with BpRAV1, providing an effective strategy to enhance drought tolerance through improved ROS scavenging capacity.